Finasteride does not help telogen effluvium.

Finasteride does not help telogen effluvium. The mechanism is wrong.

Pattern hair loss is DHT shrinking follicles over years. Finasteride blocks DHT production, so it works.

Telogen effluvium is something else entirely. A trigger (illness, severe stress, childbirth, sudden weight loss, new medication, iron deficiency) pushes a large fraction of growing follicles into the resting (telogen) phase at the same time. About 2 to 4 months later, those follicles all shed together. The follicles are healthy and will resume normal cycling.

Finasteride does not affect any of this. It can be reasonable to start finasteride if pattern hair loss has been masked under the TE shed and is now visible, but it will not shorten the TE itself or prevent the recovery.

What actually shortens TE: addressing the underlying trigger if it is still present, treating low ferritin or thyroid if those came up on bloods, eating enough, and patience. Most cases resolve within 6 months of the trigger.